Recently, a cyclopolyolefin attracts attention because of its excellent optical transparency, heat resistance, mechanical strength and capability of forming a good film. Meanwhile, an organopolysiloxane is widely used as a functional polymer which is highly resistant to heat, moisture and chemicals. A polymer having both polycyclolefin backbone and polysiloxane backbones is therefore expected to have properties of the both backbones.
A cyclic functional polysiloxane can be a starting substance for preparing such a polymer. One example of the cyclic functional polysiloxane is known from WO02/062859 which describes norbornene functional polysiloxane represented by the formula shown below.

Japanese Patent Application Laid-Open No. 2003-252881 describes a silylnorbornene compound prepared by reacting a vinylsilane having an alkoxy group or a halogen group with cyclopentadiene.
Pierre M. Chevalier et al., “Ring-Opening Olefin Matathesis polymerisation (ROMP) as a Potential Cross-Linking Mechanism for Siloxane Polymers”, Journal of Inorganic and Organometallic polymers (1999), 9(3), p 151, describes the followings.

Macromolecules 1989, vol. 22, p 3205-3210, describes that the following norbornene functional tetrasiloxane is useful as an initiator for living ring-opening metathesis polymerization.

German Patent Application Publication No. DE4128932 describes that it is possible to incorporate a norbornene functional organopolysiloxane in a composition comprising an organopolysiloxane having an SiH bond and an addition reaction catalyst. However, no working example is given.
Addition-reaction polymerization is widely used, for example, for adhering or encapsulating electronic parts, and molding articles, because the reaction forms no by-product and can be progressed with extremely small amount of catalyst. However, it is known that an unsaturated bond which is not located at an end of a molecule has low reactivity and therefore not so practically useful for the polymerization. Further, reactivity of an unsaturated bond in a multi-cyclic compound has hardly been studied, in contrast to the fact that norbornene functional group has been studied much, for example, as described in J. Inorg. Organomet. Polym., Vol. 9, 3, p 151-164, 1999.